Impact of Rain Weather Conditions over Hybrid FSO/58GHz Communication Link in Tropical Region

Abstract

Free Space Optics (FSO) is a potential optical technique poised to complement traditional wireless communication. Using optical signals for point-to-point transmission, FSO offers advantages such as abundant unregulated bandwidth, high data rates, enhanced security, and lower costs than microwave links. However, attenuation due to weather conditions, particularly rain, poses a significant challenge to both FSO and RF transmission. This study proposes a Hybrid FSO/58GHz system model to address rain-induced attenuation, implementing the ITU-R FSO prediction model in Kuala Lumpur to evaluate performance in Malaysia. Utilising three years of rain intensity data from UTM, Kuala Lumpur, the study computes rain attenuation for an FSO link with a 780 nm wavelength based on the ITU-R P.1814 model. Specific attenuations for various RF frequencies are also estimated to identify a suitable frequency for the hybrid system. The study analyses the impacts of channel attenuations on both FSO and RF links to enhance system availability and data rate. Key performance metrics such as received power (Pr), signal-to-noise ratio (SNR), and bit error rate (BER) are assessed for a 1 km link. The results demonstrate the successful implementation of the FSO link based on the ITU-R model in Malaysia, identifying 58GHz as the optimal RF frequency for the hybrid system and improving performance under heavy rain conditions.

Keywords

• FSO, Rain Attenuation, Hybrid FSO/RF, Rain Intensity